Hand annotation of documents or drawings is a very natural action and even though on-screen annotation is possible in some software applications using keyboard input and on some tablet computing devices using a special pen which is sensed by the tablet, many people still choose to hand annotate paper printouts due to their low weight, low cost and ease of carrying around and passing to others. However, people then face the difficulty of incorporating the hand annotations back into electronic versions of documents.
The embodiments described below are not limited to implementations which solve any or all of the disadvantages of known methods of hand annotation.